Agriculture currently utilizes fertilizers to deliver the needed nutrients (macro and micro) to plants through the application of these fertilizers to the soil. Fertilizers can be formulated as man-made products and/or natural organic based animal manure. These nutrients are absorbed from soil by plants to sustain their growth. Phosphorous is second to nitrogen as the most limiting macronutrient. In the case of phosphorus fertilizer, 40% of landscape soil is considered to contain inadequate levels of phosphorus for woody plant growth. Moreover, most of the phosphorus is largely inaccessible as it is in a form that is not soluble in water (and thus are not available to plants). In some cases, only 0.01% of the total soil phosphorus is in the form of a water soluble ion, the only form which can be absorbed by the plant. Adequate and accessible soil phosphorus is essential for optimal crop yields. Phosphorus enables a plant to store and transfer energy, promotes root, flower and fruit development, and allows early maturity. Phosphorus is also involved in many processes critical to plant development such as photosynthesis where plants utilize organic phosphorous compounds when converting sunlight to energy. Without enough phosphorus present in the soil, plants cannot grow sufficient root structure, which is key to the plant's ability to absorb water and nutrients from the soil. Moreover, woody plants without sufficient root structure cannot maintain an equilibrium between roots and shoots, which is key to surviving drought, windy weather, and/or pests. Other nutrients such as calcium, magnesium, sulfur, manganese, zinc, iron, and the like can also be locked into the soil in insoluble salts and complexes. Often, these nutrient-insoluble salts and complexes contain a phosphate anion that results from the reaction of fertilizer components containing mono and/or di-ammonium phosphates with metal cations when the fertilizer is applied to the soil. The presence of water in the soil provides an ideal medium, promoting the reaction that results in the formation of these insoluble salts and complexes.
Because fertilizers containing phosphorus are important in agriculture, it would seem that using more stable cations (such as sodium and/or potassium phosphates) versus the largely unstable ammonium phosphate would tend to limit the formation of these insoluble salts and complexes, leading to less pollution (and more available phosphorous for plants). However, in practice, the relatively high solubility of the ammonia, sodium and/or potassium phosphate cause them to be released into our waterways, creating deleterious effects. One such effect of water soluble phosphorus salts that is washed into lakes or rivers is eutrophication. Eutrophication occurs in a lake or river when undesirable algae and/or underwater weeds grow as the result of increased nutrient supply. This generally causes low water oxygen concentrations and clogged waterways, which sometimes leads to the loss of aquatic animals (such as fish) and other aquatic plants.
To address this issue, some states (in the US) and countries are beginning to regulate the usage of phosphorus in fertilizers to decrease eutrophication. Thus, it would desirable to optimize fertilizer performance so that the requisite amount of nutrients (including phosphorous) be delivered to soil in a timely manner thereby allowing plants to grow at levels that are economically and environmentally viable. Accordingly, a fertilizer additive that will allow the slow conversion and release of the requisite nutrients (that may be in the form of insoluble salts and complexes) will not only decrease the degree of pollution, but it will also reduce the cost of the fertilizer by improving efficiency in a time sensitive manner allowing the requisite nutrients to be released over a longer duration of time. The advantage of this additive would be that nutrients would be more readily available over longer time periods, resulting in plants that are not only healthy and grow well, but ultimately produce higher yields.